Baseball Math

Here’s a simple arithmetic question:

“A bat and ball cost $1.10. The bat costs $1 more than the ball. How much does the ball cost?”

The vast majority of people respond quickly and confidently, that the ball costs 10 cents.

This answer, which seems so obvious, is absolutely wrong.

Education doesn’t really help, either - more than 50% of students at Harvard, Princeton and the Massachusetts Institute of Technology routinely give the incorrect answer.

Daniel Kahneman, a Nobel Laureate and professor of psychology at Princeton, has been asking questions like this for more than five decades. His experiments have profoundly changed the way that we think about thinking.

While philosophers, economists and social scientists have assumed for centuries that human beings are rational agents, Mr. Kahneman and his little quizzes  demonstrate that we’re not nearly as rational as we like to believe – often taking intuitive “shortcuts” that can, as in the example above, lead us astray.

(The correct answer, by the way,  is five cents for the ball and $1.05 for the bat.)